Simply stated, unless the 16th Amendment is repealed and replaced with a new provision forever barring the re-imposition of any taxes on income, a VAT inevitably would be a new source of revenue and become a money machine to finance ever-larger government.

In some sense, it’s a version of the national sales tax, except the revenue is collected on the “value added” at each stage of the production process rather than in one fell swoop when consumers make their purchases.

And it’s also conceptually similar to the flat tax. Both have one rate. Both have no double taxation. And both (at least in theory) have no special preferences and loopholes. The difference between a flat tax and the VAT is that the former taxes your income (only one time) when you earn it and the latter taxes your income (only one time) when you spend it.

In other words, the bottom line is that it is good (or, to be more accurate, less bad) to have a tax system with a low rate and no double taxation. And in the strange world of public finance economists, a system with no double taxation is called a “consumption-base tax.” And the flat tax, sales tax, and VAT all fit in that category.

So why, then, if supporters of limited government prefer a consumption-base tax over the internal revenue code, is there so much hostility to a VAT?

The answer is simple. We don’t trust politicians and we’re afraid that a VAT would be an add-on tax rather than a replacement tax.

Which explains why it’s better to simply turn the existing tax code into a consumption-base tax. After all, the worst thing that could happen is that you degenerate back to the current system.

But if you go with a VAT, the downside risk is that America becomes France.

There’s a story in today’s Wall Street Journal that illustrates why consumption-base taxation is both a threat and opportunity. Here are some introductory excerpts.

U.S. lawmakers on both sides of the aisle increasingly are finding appeal in an ambitious concept for overhauling the nation’s income-tax system: a tax based on consumption, a tool long used around the world. …As the name implies, consumption-style taxes hit the money taxpayers spend, rather than income they receive. One prominent feature of consumption systems is that they generally tax savings and investment lightly or not at all. That, in turn, encourages more investment and innovation, and ultimately more growth, many economists contend.

The reporter is wrong about consumption systems, by the way. Income that is saved and invested is taxed. It’s just not taxed over and over again, which can happen with the current system.

But he’s right that there is bipartisan interest. And he correctly points out that some politicians want an add-on tax while others want to fix the current system.

The tax-writing Senate Finance Committee is giving new consideration to the consumption-tax idea with the hope that its promised boost to economic growth would ease the way to a revamp. …Some of these proposals would have consumers pay another tax in addition to existing state and local sales taxes, while others would merely reshape the current system to tilt it more toward consumption. …Enactment of a broad-based federal consumption tax would align the U.S. with a global trend.

A Democratic Senator from Maryland wants to augment the current tax code by imposing the VAT.

Mr. Cardin introduced legislation last year to create a type of consumption tax known as a value-added tax and at the same time lower business taxes and scrap income taxes completely for lower-income Americans.

While some GOP Senators want to modify the current system to get rid of most double taxation.

Republicans on the working group also are interested in the concept, including a proposal put forward recently by GOP Sens. Marco Rubio of Florida and Mike Lee of Utah. That plan would make several changes to the tax code that would move the nation closer to a consumption-based system. …Many GOP members “believe that there are economic benefits to moving away from taxation of income and toward taxation of consumption,” a Senate aide said.

And the story also notes the objections on the left to consumption-base taxation, as well as objections on the right to the VAT.

Some liberals are concerned that consumption taxes affect poor people disproportionately, while unduly benefiting the rich, unless adjustments are made. For their part, conservatives fear that some types of consumption tax—particularly value-added taxes—would make it too easy to dial up government revenue collection.

So what’s the bottom line? Is it true, as the headline of the story says, that “Proposals for a consumption tax gain traction in both parties”?

Yes, that’s correct. But that’s not the same as saying that there is much chance of bipartisan consensus.

There’s a huge gap between those who want a VAT as an add-on tax and those who want to reform the current system to get rid of double taxation.

This doesn’t mean we shouldn’t worry about the prospect of an add-on VAT. As I warned last year, there are some otherwise sensible people who are sympathetic to this pernicious levy.

Which is why I repeatedly share this video about the downside risk of a VAT.

And you get the same message from these amusing VAT cartoons (here,here, andhere).

1. It replaces the discriminatory “progressive” tax with a single tax rate at the lowest possible level, thus reducing the tax penalty on productive behavior.

2. It gets rid of all forms of double taxation, such as the death tax and capital gains tax, meaning economic activity is never taxed more than one time.

3. Other than a family-based allowance, it gets rid of all loopholes, deductions, credits, exemptions, exclusions, and preferences, meaning economic activity is taxed equally.

Some people say that these are also three reasons to favor a national sales tax.

My response is that they’re correct. In simple terms, a national sales tax (such as the Fair Tax) is like a flat tax but with a different collection point.

If you want more details, I often explain the two plans are different sides of the same coin. The only difference is that the flat tax takes of slice of your income as you earn it and the sales tax takes a slice of your income as you spend it. But neither plan has any double taxation of income that is saved and invested. And neither plan has loopholes to lure people into making economically irrational decisions.

So even though I’m mostly known for being an advocate of the flat tax, I have no objection to speaking in favor of a national sales tax, testifying in favor of a national sales tax, or debating in favor of a national sales tax.

With this bit of background, you can understand why it caught my attention that an economics professor at the University of Georgia (Go Dawgs!) wrote a column for Forbes with the provocative title of “I Will Support The Fair Tax When Its Backers Tell The Truth”.

Professor Dorfman writes that “such a consumption tax has much to recommend it from an economic point of view” but then warns that he “cannot support the Fair Tax as long as its backers continue to make implausible claims for their proposed reform.”

So what are the implausible claims? Let’s check them out and see if his friendly criticism is warranted.

He first expresses skepticism about the claim that take-home pay will rise to the level of gross pay under a Fair Tax, particularly given the assertion that prices won’t rise.

…the odds are that your gross pay will shrink over time under the Fair Tax. …employers can offer workers lower pay because of the lower cost of living (same prices, but higher take home pay). Because workers evaluate pay offers based on the purchasing power of that pay, the same competitive forces that will lower prices after the removal of business taxes, will lead to lower pay for employees in the long run as the labor market adjusts.

I suspect Professor Dorfman’s critique is correct, but I don’t think it matters. Workers understandably care first and foremost about the purchasing power of their paycheck, and that won’t be negatively impacted.

The Professor than looks at whether the Fair Tax gets taxes the underground economy.

…let’s tackle the claim that the Fair tax will do a better job of collecting taxes on criminals, the underground economy, and those who underreport their income. The idea is that people may hide some of their income or that drug dealers and others in the underground economy do not report their income, but that everyone spends money so the Fair Tax will tax everyone. Unfortunately, this claim is not true… Retailers are just as capable of underreporting revenue and not sending in the corresponding Fair Tax as people are of underreporting their income. …The incentive to avoid such consumption taxes will only increase when the rate is four or five times what it is now. If you don’t believe consumption taxes suffer from collection problems, go ask Greece.

And he looks specifically at taxing criminal activity.

Another reason that the Fair Tax will not capture extra revenue from illegal activities is that it only switches which side of the transaction is missed by the tax system. Currently, while drug dealers may not report their income, the people who buy drugs are paying with after-tax income. Under the Fair Tax, the drug dealers will pay tax when they spend their drug profits. However, unless the drug dealer sends in the Fair Tax on their sales, the drug buyers will now avoid tax on their purchases. Under either tax system, one side of the underground transactions will be paying taxes and one will not.

I think Professor Dorfman is correct, particularly in his explanation that drug dealers and other criminals will not collect sales tax when they peddle their illicit goods.

And he’s also correct when he says that the Fair Tax won’t collect all taxes on legal products.

But not zero evasion, so Fair Tax supporters exaggerate if they make that claim.

The next point of contention is whether the IRS can be repealed under a Fair Tax.

…some agency needs to collect all the sales taxes, ensure retailers are sending in the full amount, and handle all the mechanics of the prebate. The prebate requires this federal agency to know everyone’s family size and have a bank account or other method of sending out the prebate each month. So while individuals will have less interaction with the federal tax agency, there will still be some. For retail businesses, their interactions with federal tax officials will be at least as much as now, if not more.

The Professor is right, though this may be a matter of semantics. Fair Tax people acknowledge there will be a tax collector (the legislation creates an incentive for states to be in charge of collecting the tax), but they say that the tax authority under their system will be completely different than the abusive IRS we have today.

Last but not least is the controversy over whether everyone benefits under a Fair Tax.

…while Fair Tax proponents often act like nobody loses under the Fair Tax that is simply not possible. If the Fair Tax is implemented in a revenue neutral manner (collecting the same amount of total revenue as all the taxes it replaces), and some people win then other people must lose. Poor people pay roughly no tax either way, so the Fair tax would be neutral for them. The very rich will assumedly pay less since they spend a lower percentage of their income and spend more overseas. Thus, the suspicion is that the middle class will be paying more. One other group pretty sure to pay more is the elderly. The elderly have paid income tax while earning income, and under the Fair Tax would suddenly pay high consumption taxes right when their income drops and their spending increases. In the long run, this is not a problem, but early in a Fair Tax regime, the elderly definitely are losers.

Once again, Professor Dorfman is making a good point (and others have made the same point about the flat tax).

My response, for what it’s worth, is that supporters of both the flat tax and national sales tax should not be bound by revenue neutrality. Especially if the revenue-estimating system is rigged to produce bad numbers. Instead, they should set the rate sufficiently low that the overwhelming majority of taxpayers are net winners.

And in the long run, everyone can be a net winner if the economy grows faster.

And that, as Professor Dorfman agrees, is the main reason for tax reform.

The Fair Tax really has much to recommend it. It is simpler than the current system. It causes fewer distortions in the daily economic decisions that people make. The main distortion it does introduce is positive: to encourage saving and discourage consumption which would make the country wealthier in the long run.

Though I would quibble with the wording of this last excerpt. I don’t think the Fair Tax creates a pro-savings distortion. Instead, it removes an anti-savings bias. Just like the flat tax.

Advocates of the Fair Tax correctly say that their proposal shouldn’t be implemented until and unless the income tax is fully repealed. But as I explain in this video, that may be an impossible undertaking.

P.S. Actually, what I really want is avery small federal government, which presumably could be financed without any broad-based tax. Our nation enjoyed strong growth before that dark day in 1913 when the income tax was imposed, so why concede that politicians today should have either a flat tax or Fair Tax? But that’s an issue for another day.

My modest contribution was to present “The Case for the Flat Tax,” and I was matched up – at least indirectly, since there were several hours between our presentations – against former Congressman John Linder, who gave “The Case for the Fair Tax.”

For all intents and purposes the flat tax and sales tax are different sides of the same coin. The only real difference is the collection point. The flat tax takes a bite of your income as it is earned and the sales tax takes a bite of your income as it is spent.

That being said, I do have a couple of qualms about the Fair Tax and other national sales tax plans.

First, I don’t trust politicians. I can envision the crowd in Washington adopting a national sales tax (or VAT) while promising to phase out the income tax over a couple of years. But I’m afraid they’ll discover some “temporary” emergency reason to keep the income tax, followed by another “short-term” excuse. And when the dust settles, we’ll be stuck with both an income tax and a sales tax.

To be sure, there are downside risks to the flat tax. It’s quite possible, after all, that we could get a flat tax and then degenerate back to something resembling the current system (though that’s still better than being France!).

On dozens of occasions over the past 15-plus years, I’ve had to explain to reporters that why anti-sales tax demagoguery is wrong.

So I hope it’s clear that I’m not opposed to the concept. Heck, I’ve testified before Congress about the benefits of a national sales tax and I’ve debated on C-Span about how the national sales tax is far better than the current system.

Actually, what I want is a very small federal government, which presumably could be financed without any broad-based tax, but that’s an issue for another day.

Returning to the issue of tax reform, there’s no significant economic difference between the flat tax and the sales tax. What we’re really debating is how to replace the squalid internal revenue code with something worthy of a great nation.

And if there are two paths to the same destination and one involves crossing an alligator-infested swamp and the other requires a stroll through a meadow filled with kittens and butterflies, I know which one I’m going to choose. Okay, a slight exaggeration, but I think you get my point.

But my job is to do the right thing and bring truth to the economic heathens, so I agreed to participate. And I’m glad I did, because it gave me a chance to try out a new argument that I hope will educate more people about the perverse impact of double taxation.

Let me know what you think of this approach, which asks people whether they would think it would be fair if they couldn’t take credit for withheld taxes when filling out their 1040 tax return.

Capital gains taxes and dividend taxes are both forms of double taxation. That income already is hit by the 35 percent corporate income tax. So the real tax rate for people like Mitt Romney is closer to 45 percent. And if you add the death tax to the equation, the effective tax rate begins to approach 60 percent. Here’s a simply analogy. Imagine you make $50,000 per year and your employer withholds $5,000 for personal income tax. How would you feel if the IRS then told you that your income was $45,000 and you had to pay full tax on that amount, and that you weren’t allowed to count the $5,000 withholding when you filled out your 1040 form? You would be outraged, correctly yelling and screaming that you should be allowed to count those withheld tax payments. Welcome to the world of double taxation.

I’m very enthusiastic – but also a little worried – about Herman Cain’s tax plan.

So when I got the opportunity to write a short column for the New York Times, I explained that his proposal was very good tax policy, in large part because it is based on the same principles as the flat tax.

But I then expressed my concern that the 9-9-9 plan might morph into something we don’t want.

This doesn’t mean Cain’s tax plan is perfect. The biggest concern, at least from many on the right, is that he would allow the crowd in Washington to simultaneously impose a flat tax, a national sales tax and (apparently) a form of value-added tax. This might not be a problem if there was some way of guaranteeing that none of the rates could ever climb above 9 percent. Unfortunately, the European experience (especially with VATs) does not leave much room for optimism. Sooner or later, politicians who want bigger government can’t resist pushing tax rates higher. And when the dust settles, you become Greece. Which is why Cain should not have reinvented the wheel. If he wants a low rate, no double taxation and no loopholes, the flat tax has all the upsides and none of the downsides of the 9-9-9 plan.

My basic message is that 9-9-9 should be turned into a postcard because the flat tax is a safer way of achieving the same goals.

The worst thing that can happen with a flat tax, after all, is that politicians begin to re-install loopholes and re-impose discriminatory rates and we wind up with something that looks like the current system.

But it seems that I was too nice in my analysis of Mr. Cain’s plan. Josh Barro and Bruce Bartlett are both claiming that the business portion of Cain’s 9-9-9 is a value-added tax (VAT) rather than a corporate income tax.

Let’s elaborate. The business portion of Cain’s plan apparently does not allow employers to deduct wages and salaries, which means – for all intents and purposes – that they would levy a 9 percent withholding tax on employee compensation. And that would be in addition to the 9 percent they presumably would withhold for the flat tax portion of Cain’s plan.

Employers use withholding in the current system, of course, but at least taxpayers are given credit for all that withheld tax when filling out their 1040 tax forms. Under Cain’s 9-9-9 plan, however, employees would only get credit for monies withheld for the flat tax.

In other words, there are two income taxes in Cain’s plan – the 9 percent flat tax and the hidden 9 percent income tax that is part of the VAT (this hidden income tax on wages and salaries, by the way, is a defining feature of a VAT).

This doesn’t make Cain’s plan bad from a theoretical perspective. The underlying principles are still sound – low tax rates, no double taxation, and no loopholes.

But if I was uneasy when I thought that the 9-9-9 plan added a sales tax on top of the income tax, then I am super-duper-double-secret-probation uneasy about adding a sales tax and a VAT on top of the income tax.

Here’s my video on the VAT, which will help you realize why this pernicious tax would be a big mistake.

Again, this doesn’t make Cain wrong if we’re grading based on economics or philosophy. My anxiety is a matter of real-world political analysis. I don’t trust politicians with new sources of revenue. Whether we give them big new sources of revenue or small new sources of revenue, they will always figure out ways of pushing up the tax rates so they can waste more money trying to buy votes.